I am aware of some positive endings, but in all of those cases, the therapy itself was not crossing any ethical boundaries. My opinion and experience is that the ethics of the therapy is a good sign of the therapist's character. I don't know a single story of someone who was seeing a therapist who crossed ethical therapy boundaries with that person in any way & it turned into a healthy friendship.

As for the 2-year rule, the general idea, I believe, is that it's time for everyone to move on.

My current T has a "T for life" rule - he will never be a client's friend, period. Doesn't mean no contact once therapy has ended, but he will always be my therapist - even if my therapist who I am not seeing any longer.